Dynamoelectric machine assembly



Nov. 26, N4@ a-a. G. HAMlLroN ET A1.

DYNAMOELECTRIC MACHINE ASSEMBLY Filed Aug. 31, 1945 2 SheeS-Shee. l

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H. G. HAMILTON ET AL DYNAMOELECTRIC MACHINE ASSEMBLY Filed Aug. 51, 1943 2 Sheets-Sheet 2 I'- INVENTORS 75 Hugh @Hamilton Leonard C11-Tratti 'and'.)lfreckroblach Patented Nov. 26, 1946 2,411,684 DYNAMOELECTRIC MACHINE ASSEIWIBLY irlugb. G. Hamilton and Leonard C. Pratt, Baldwin,

' and Alfred Skrobisch, New York, N. Y., assignors to Eastern Ali- Devices, Inc., Brooklyn, N. Y., a corporation ol' New York Application August 31, 1943, Serial N0. 500,636

il. Claims.

This invention relates to the manufacture of electric motors and has special reference to the provision of an improved method of constructing and assembling motors such as induction motors and to the improved resulting motor structures and assemblies.

The prime object of the present invention centers about the structural designing of the component parts of the motor, namely, the stator unit, the rotor unit and the motor casing so that these may be capable:

(a) of being assembled rapidly by mass production technique;

(b) of being put together to form strong and rigid motor structures, having the capacities for rough handling and durable use and (c) of being built to produce a motor having an exceedingly smooth running operation and a good ratio of power to size.

To the accomplishment of this prime object and such other objects as may hereinafter appear, the invention is directed to the method of constructing and assembling electrical motors and to the motor structures set forth in the iollowing specification and as sought to be dened in the appended claims. accompanied by drawings in which:

Fig. 1 is a longitudinal cross-sectional View of one form of assembled motor embodying the structural principles of our present invention;

Fig. 2 is a view portraying a step in the assemiling of the stator unit and parts of the casing oi the motor, the said parts being shown in longitudinal cross-section;

Fig. 3 is a View of the rotor used with this motor;

Fig. 4 is a view of an assembling plug used in the step of assembling the parts of Fig. 2;

Fig. 5 is a view depicting a subsequent assembly step and showing the manner in which the assembling of the stator and the motorl casing is completed, the parts of this View being shown in vlongitudinal cross-section;

Fig. 8 is a perspective view of one of the end covers of the motor casing;

Fig. '7 is a perspective view of the other of the end covers of the motor casing;

Fig. .8 is a longitudinal cross-sectional View of a nodied form of motorl also embodying the structural principles of the present invention;

Fig. 9 is a view of Fig, 8 taken on a reduced scale and in cross-section in the planes of the broken line 9 9 of Fig. 8;

Fig. 10 is an interior View of one of the end covers used in the motor of this modication;

The specification is Fig. 1l is a view of Fig. 10 taken in cross-section in the plane of the line lll-i! oi Fig. 10;

Fig. 12 is an exterior view of the other end cover used in. the motor of this modification; and

Fig. 13 is a View of the latter taken in cross-section in the plane of the i'ine itii3 oi' lng. 12.

Referring now more in detail to the drawings and having rei'erence first to the form of invention depicted in Figs. i to 'Z thereof, the motor comprises trie stator unit generally designated as S, the rotor unit generally designated as R and the casing generally designated as C: for housing and supporting both the stator and rotor units, these component parts or" the motor being constructed and associated to carry out the purposes of the invention above referred to. The motor illustrated in these iigures of the drawings is a synchronous motor having an induction type rotor, the motor depicted being capable ot operating on an A. C. supply line oi' llo volts and ed@ cycles.

The stator S comprises a coil structure 2@ supported in a laminated core the laminations oi which are assembled within and secured to a metal such as an aluminum shell 2t. This stator unit is in itself assembled in. an improved way. A group of plate shaped laminations z2 are stacked in a drawn aluminum cup 2Q which has one end 26 thereof already formed inwardly to make the supporting shoulder ior the laminations. This cup itl with the laminations therein 'is then forced through a sizing die which is a little smaller in diameter than the cup, with the result that the aluminum cup is tightly squeezed against the laminations, thus binding all the laminations securely in place. The laminations are so cut that when thus assembled there are provided the spaced longitudinally arranged grooves 2B into which the individual coils are inserted. The coils are grouped and connected at their opposite ends (at the ends of the laminated assembly) to form what has been designated as the coll structure 2t from which emanate the conductors or leads 38. The aluminum cup or shell 2t provides end abutable surfaces or edges, namely, the outer face oi the inturned shoulder 26 and the opposite edge 32. It `will be noted that in this form of the invention, due to the fact that the laminated assembly is tightly held by the cup, this end 32 of the cup need not be inwardly turned or spun over and may remain in the condition depicted in the drawings.

The rotor R separately shown in Figli? com- 3 prises an induction motor type rotor element 34 fixed to a rotor shaft 38. The surface of the rotor element may be milled or ground to form the slots or flats 38 so as to define salient poles.v

On the opposite ends of the'rotor shaft are preferably mounted the ball bearings 40 and 42 both preferably of the radial type, the ball bearing 48 having an outside diameter smaller than that of the diameter'of the rotor element 34, while the ball bearing 42 has an external diameter either equal to or greater than, that is, at least equal to, the diameter of the rotor element 34, all for a purpose to be described hereinafter.

The casing C comprises a tubular casing section 44, a front end cover 46 and a rear end cover 48, the ends of the tubular casing section 44 being secured to the front and rear end covers by inturning or spinning over the ends 58 and 52 of the tubular casing into engagement with the end covers. The front end cover 46 separately shown in Fig. 7 of the drawings comprises a peripherally flanged and centrally bossed velement and the rear ed cover 48 separately -tral bearing hole for the external bearing of the ball bearing 40.

The stator S, the rotor R and the casing C are so structurally designed as to enable the assembling of these component parts of the motor in the manner depicted in Figs. 2 to 5 of the drawings. The bearing hole h' defined by the central boss 56 has a diameter at least equal (equal to or greater than) to'that of the bore b of the stator unit S. The bearing hole h2 defined by the central boss 60 has a diameter no greater than and preferably smaller than the diameter `of the stator bore b. The inside edge 62 of the front end cover is machined so that it will snugly abut the adjacent edge, namely,

the shoulder. 25, of the stator cup or shell 24.4

Similarly, the inside edge 64 of the rear end cover is formed to snugly abut the adjacent end, namely, the edge 32, of the stator cup or shell 24. With this structural design of these parts;V

the front end cover 46, the stator unit S and the rear end cover 48 are mountable or receivable on an aligningV plug P (separately shown in Fig. 4), the aligning plug being provided with a supporting iiange 66, a part 68 for fitting the front end cover hole h', a part 'l0 for fitting the bore b of the stator unit, a part I2 for tting the hole h2 of the rear end cover, and a threaded part 'i4 for receiving a temporary locking nut 16 (see Fig. 5). The plug P thereby serves as an aligning and an assembling plug for the front end cover, the stator unit and the rear end cover. These are assembled on the aligning plug in sequential abutting relation as best shown in Fig. 5 of the drawings, the inner edges 62 and 64 of the end covers snugly abutting against the contiguous ends 28 and 32 of the 'stator cup. When thus assembled, the Alock nut 16 temporarily holds these parts in the assembled and accurately aligned condition. f

When thus aligned and assembledfthe tubular casing section 44 is then placed over the assem- 4 bly and secured in position. The end portions 44 and 442 of this tubular casing 44 have an internal diameter (or diameters) the same as the external diameters of the flanges 58 and 84 of the end covers 48 and 46 respectively, whereby these end portions of the tubular casing accurately fit the outside walls or flanges of the end lcovers. In the form of the invention shown in Fig. 1, the outside diameter of the stator cup or shell 24 is the same as that or those of the ilanges of the end covers so that the tubular casing 44 when slipped over the assembly shown in Fig. 5 snugly fits and encases the two end covers and the stator unit. At this point or step of the assembling operations, the edges 88 and 52 of the tubular casing are then swaged or spun over and lnturned into engagement with the front faces or seats in the front and rear end covers 48 and 48, respectively, as is most clearly shown, for example, in Figs. 1 and 5 of the drawings. The tubular casing may be originally formed with the flanged edge 58 in which case the edge 52 is spun over in this step of the assembling operations. This inturning of the casing edges secures together the tubular casing, the end coversand the stator units into a stator and casing assembly. When this is done, the temporary nut i8 is removed and the plug P is withdrawn. By -virtue of the fact that the bearing hole h is either equal to or larger than the stator bore b and also by virtue of the fact 4that the bearing hole h2 is no greater and is preferably less than the stator bore b, the plug P may be both inserted for its aligning function and withdrawn after the stator and casing assembly best depicted in Fig. 5 has been produced.

With the removal of the aligning and assembling plug P, the rotor R separately shown in Fig. 3 may now be substituted for the plug. Since the external bearings of the ball bearings 48 and 42 accurately t and, therefore, may be snugly seated in the boring holes h3 and h', the rotor R thus simply replaces the plug P. It will be understood that the rotor unit 34 is somewhat smaller in diameter than the corresponding part 'i8 of the plug P to provide the necessary rotation clearance for the rotor. When the rotor R is thus inserted, it may be held in position by a spring plate 18, a washer 80 and a locking ring 82 (see Fig. 1) which locking ring is received by a groove 84 in the front end plate. In the assembling of the parts, the leads or conductors are first threaded through suitable orifices 86 provided in the rear end cover 48. These may be soldered to connectors 88 which are mounted on an insulation plate 98 and affixed as by means of rivets 92 'to the rear end cover (see Fig. 1). 94 is a name plate which may be secured in position by means of some of these rivets.

By means of this provided structure, it will be observed that the following results are achieved: The stator unit S, the casing C (and its component parts) and the rotor R are assembled to produce the motor unit shown in Fig. 1 by very rapid assembling methods embodying the simplied steps depicted in Figs. 2 to 5 of the drawings. The motor may thus be assembled with speed and efiiciency by mass productiontechnique. The stator and casing assembly produced in the steps shown in Fig. 5 forms a very rigid and strong unit. The bearing holes as well as the stator bore of this assembly are perfectly aligned. This together with the rigid frame structure provided (the stator and casing assembly) renders possible not only the substantially perfect alignment and mounting of the rotor R in the motor, but also renders possible a smooth running operating rotor and a support therefor which resists any frame altering or distorting strains. A motor unit thus results which is strong and sturdy, capable of being subjected to rough handling and which is very durable in use. By means of the simple assembling methodsafforded, the unit may be made economically.

In Figs. 8 to 13 of the drawings I show a modified form of motor embodying the structural principles of the invention. In this modification, the motor is constructed to provide paths therein for the circulation therethrough of a cooling medium (such as air) induced therefthrough by the provision of a blower or fan associated with the motor. ln this form of the invention, this path for the circulation of the cooling medium includes an annular space between the motor casing and the stator unit. The structural principles of the invention above described are nevertheless carried out in conjunction with the provision of cooling mechanism for the motor. This forni of the invention is applied to an induction motor capable oi operating irom an A. C. supply or llo volts andellll cycles. in this modification, the motor comprises a stator unit ing C inciudins` the front end cover and the rear end cover 18. PThe stator S' embodies a construction substantially the same as or similar to the stator S previously described, except that in this modiilcation the stator cup or shell ist in addition to having its front end inturned to produce an abuttingshoulder itt, has its rear end also inturned to provide an abutting shoulder Mld. The rotor Pl is similar in construction to the rotor R above described, the rotor E' including the rotor shaft m6, the front ball bearing i052 and the rear ball bearing l it. To provide for a path for the circulating of a cooling medium through the motor parts as indicated by the new arrows M2 shown in Fig. 8 of the drawings, the end covers @E and @t are constructed as best shown in Figs. lll to lo of the drawings and are related to the stator S and the tubular section llt ci the casing C in a manner presently to be described.

,The front end cover @t is provided with a flange or rim il@ having an external diameter equal to the internal diameter oi the adjacent portion of the tubular casing il@ and is provided with a seat llt for receiving the spun or inturned end H2@ oi' this end or the tubular casing iid. This iront end cover is also provided with a plurality 'of inset legs lill, each provided with an angular seat ld, these seats, disposed circumierentially, serving to receivingly seat the casinar shoulder lil?. The front end cover il@ is also provided with the central boss llt which defines the bearing hole h3, this being similar in structure and ourn pose to the corresponding parts of the front end cover il@ previously described. The rear end cover @il is provided with the flange or rim lili having an outside diameter equal to the inside diameter of the rear end of the tubular casing i ill so as to snugly iit the same, and is provided with a shoulder seat l@ over which the rear end t ES', a casing C' and a rotor unit R', the said casit or" the tubular casing iM is spun or inturned,

cover is provided with a centrally arranged boss ISB which defines the smaller bearing hole h4 similar in structure and purpose to the form of the invention above described.

By means of this recited construction, the end covers 96 and S8 may be assembled as before in longitudinal abutting relation with the bearing holes of the end covers and the bore of the stator perfectly aligned, the stator S in this case being, however, sosupported by the end covers 96 and 88 that while the tubular casing IH may be secured to the end covers as before to produce a unified and rigid assembly, the stator unit S' is, however, spaced from the tubular casing H4 by an annular space Hill, the outside diameter of the stator cup its in this case being to this extent smaller than the inside diameter of the tubular casing i M.' The spacing oi. the legs 522 oil the front end cover te dennes orifices or openings therein arranged circumferentially oi the end cover, which register with a series of circumferential openings or orices M2 formed in the tubular casing section litt. The rea;1 end cover d8 is provided towards its center wltha plurality of oriiices idd, '.here is thus rprovided a ilow path for a cooling niediunfi.v The air or other cooling medium enters through the orifices M2, passes the openings donned by the .legs i222, iinpnges against the end turns of the stator coils and then ilov/s rearwardly through the motor in the space lll@ between stator and the casing shell, and then over and striiring 'the end turns at the rear end of the stator and out 'through the orifices iflll in the rear end cover. rfln efficient method ci cooling is thus provided in a structure 'which enables all oi' the constructional principles of the invention to be employed.

For inducing the circulation ci the cooling me diurn, this motor is provided with a blower or fan lil@ having a hub Wi mounted on an exten-u LUJO lsion loll of the rotor shaft, the said blower being provided with the vanes Encasing this 'slower is ablower cover l l detachably attached to the rear end cover as by means of screws E56. This blower cover is provided with the circumferentially arranged orifices H53 through which the air centriugally acted upon by the blower exits, asbest shown in Fig. ci the drawings. form of the invention, the leads or conductors may be threaded through one of the openings 62.

The method of constructinsl and assembling electric motors and the resulting motor assernn blies embodying the principles of the present inn vention, and the man advantages thereof, both from the standpoint l manufacturing method. endconsumineuse, will the main be fully afp parent from the above detailed description thereof. l`t will be further apparent that while we have shown and described the principle@ of the invention i; connection with the 'making oi elec tric motors, the same principles will govern the construction and assembling or similar units in-i tended as generators instead of motors. lt will be understood that such changes and other changes that may 4be made without departing from the spirit lof the present invention, are in-a tended to be covered by the following claims.

We claim: l. A motor assembly comprising a front end cover, a stator unit and a rear end cover, assembled and arranged in abutting relation, central bearing holes in the end covers and the bore of the stator' unit being in alignment, a tubular casing shell the end portions or which nt over the annees ends or the tubular casing are -inturned into en sagement with the end covers to secure together the casing, stator unit and end covers.

3. A motor assembly comprising e, front end cover, a stator unit and a rear end cover assembled and arranged in abutting relation. central bearing holes in the end covers and the bore of the stator unit being in alignment, the said end covers and stator unit having the same outside diameter, a tubular casing shell ntting and ex= tending over the assembled end covers and the stator unit, the ends of the tubular casing shell being secured to the end covers to complete the assembly of and to secure together the casing, stator unit and end covers, and a rotor unit in serted into the said assembly, the said rotor unit having end bearings mating with the bearing holes of the said end covers.

d. A motor assembly comprising a iront end cover, a stator unit and a rear end cover assembled and arranged in abutting relation, central bearing holes in the end covers and the bore or the stator unit being in alignment, the said end covers having the same outside diameter and the said stator unit having an outside diameter smaller than that of the end covers, a tubular casing shell the end portions of which ilt over theoutside walls of the end covers arranged and extending over the assembled end covers and stator unit, the ends of the tubular casing being se-1 cured to the end covers to complete the assem bly of and to secure together the casing, stator 5. A motor assembly comprising a front end I cover, a stator unit and a rear end cover, assembled and arranged in abutting relation, the said end covers having side anges which abut edge walls of the stator unit, central bearing holes in theend covers and the bore of the stator unit being in alignment, the anges of said end covers being of the same outside diameter, a tubular casing shell closely tting over the anges of the end covers arranged over the assembled end covers and the stator unit, the ends of the tubular casing shell being secured to the end covers to complete the assembly of and to secure together the casing, stator unit and end covers, and a rotor unit inserted into the said assembly, the said rotor unit having end bearings mating with the bearing holes of the said end covers.

6. A motor -assembly comprising a front end cover, a stator unit and a rear end cover, assembled and arranged in abutting relation, .the said end covers having side flanges which abut edge walls of the stator unit, central bearing holes in .the end covers and the bore of the stator unit being in alignment, the flanges of said end covers and the outside wall of the stator unit being of the same outside diameter, a tubular casing shell closely tting vover the anges of the end covers and the outside wall of the stator unit, the ends of the tubular casing shell being inturned into ensagement with seats provided in the endcovers to complete the assembly of and to secure together the casing, stator unit and end covers.- and a rotor unit inserted into thesaid assembly, the said rotor unit having end bearings mating with the bearing holes of the said end covers.

'E'. A motor assembly comprising a front end cover, a stator unit and a rear end cover, assembledV and arranged in abutting relation, central bearing holes in the end covers and the bore of the stator unit being in alignment and the beena ing hole or one end cover being at least equal in diameter to that oi the bore of the stator unit, a tubular casing shell the end portions of which `:dit over the outside walls of the end covers arranged and extending over the assembled end covers and the stator unit, the ends of the ytubular bearing holes in the end covers and the bore of' y the stator unit being in alignment, a tubular casing shell the end portions of which :dt over the outside walls of the end covers arranged and extending over .the assembled endcovers and the stator unit. the outside wall oi the stator unit being oi less diameter .than the inside wall of the tubular casing to provide an annular space therebetween, oriiices in the end covers communicating with said space and providing a path for circulating a cooling medium through the casing and around the stator unit, .the ends of the tubular casing being secured to Ithe end covers to complete the assembly of and to secure together the casing, stator unit and end covers, and a rotor unit inserted into the said assembly, Ithe said rotor unit having end bearings mating with the bear` ing holes of said end covers.

9. A motor assembly comprising a front end cover, a stator unit and a rear end cover, assembled and arranged in abutting relation, central bearing holes in the end covers and the bore of the stator unit being in alignment, a tubular casing shell the end portions of which fit over the outside walls of .the end covers arranged and extending over the assembled end covers and the stator unit, the outside wall of the stator unit being of less diameter than the inside wall of the tubular casing to provide an annular space therebetween, orifices in the end covers communicating with said space and providing a path for circulating a cooling medium through-the casing and around the stator unit, the ends of the tubular casing being secured to the end covers to complete the assembly of and to secure together the casing, stator unitand end covers, a rotor unit inserted into the said assembly, the said rotor unit having end bearings mating with the bearing holes of said end covers, a blower attached Ito an end of the rotor unit, and a, blower cover encasing the same and secured to the end cover at said rotor end.

10. A motor assembly comprising a front end cover, a stator unit and a rear end cover assembled and arranged in abutting relation, central bearing holes in the end covers and the bore of the stator unit being in alignment, a tubular casing the end portions of which t over the outside walls of .the end covers arranged and extending over the assembled end covers and the stator unit, the outside wall of the stator unit being of less diameter than the inside wall of the tubular casing to provide an annular space therebetween, orifices in the end covers communicating with said space and providing a path for circulating a cooling media through the casing and around .the stator unit, the orifices in one end cover being at its circumference and in the other end cover towards its center, the ends of the tubular casing being secured to the end covers to complete the assembly of and to secure together the casing, stator unit and end covers, a rotor unit inserted into the said assembly, the said rotor unit having.

end bearings mating with the bearing holes of said end covers, a blower attached to the end of the rotor unit at the said other end cover, and a blower cover provided with circumferential openings secured to said other end cover.

11` A motor assembly comprising a front end cover. a stator unit and a rear end cover, assembled and arranged in abutting relation, a tubular casing shell the end portions of which fit over the outside walls of the end covers arranged over the assembled end covers and the stator unit, the outside Wall of the stator unit being of less diameter than Ithe inside wall of the tubular casing to provide an annular space therebetween, orifices in the end covers communicating with said space and providing a :path for circulating a cooling media through the casing and around the stator unit, the ends of the tubular casing being secured to the end covers to complete the assembly of and to secure together the casing, stator unit and end cover, and a rotor unit inserted into the said assembly.

HUGH G. HAMILTON.

LEONARD C. PRA'I'I.

ALFRED SKROBISCH. 

